Sound intensity level or acoustic intensity level is a logarithmic measure of the sound intensity (measured in W/m2), in comparison to a reference level.
The measure of a ratio of two sound intensities is
where I1 and I0 are the intensities.
The sound intensity level is given the letter "LI" and is measured in "dB". The decibel is a dimensionless quantity.
If I0 is the standard reference sound intensity
(W = watt), then instead of "dB SPL" we use "dB SIL". (SIL = sound intensity level).
Read more about this topic: Sound Intensity
Famous quotes containing the words sound, intensity and/or level:
“Wild as it was, it was hard for me to get rid of the associations of the settlements. Any steady and monotonous sound, to which I did not distinctly attend, passed for a sound of human industry.... Our minds anywhere, when left to themselves, are always thus busily drawing conclusions from false premises.”
—Henry David Thoreau (1817–1862)
“To revolt is a natural tendency of life. Even a worm turns against the foot that crushes it. In general, the vitality and relative dignity of an animal can be measured by the intensity of its instinct to revolt.”
—Mikhail Bakunin (1814–1876)
“Success four flights Thursday morning all against twenty one mile wind started from Level with engine power alone speed through air thirty one miles longest 57 second inform Press home Christmas.”
—Orville Wright (1871–1948)